The CFAR Flow Cytometry/Cell Sorting Core is referred to as the "CFAR Flow Core". About half of the use of the CFAR Flow Core is for cell sorting and the remaining half is for flow cytometric analysis. The flow cytometer used for most CFAR-supported investigations is a dual-laser FACStar plus. This instrument permits sorting of cells from HIV-infected people and sorting of cultured cells infected in vitro with HIV. The flow cytometry technician who assists users with most experiments has eight years of flow cytometry experience and a specialization in cell sorting. The full-time effort of this technician is central to the operation of the CFAR Flow Core. A biosafety program to protect the operator and the researching during cell sorting of biohazardous samples includes an isolated room with negative pressure, barrier protection of the operator and the researchers present in the room during the sort, meticulous machine maintenance to avoid delays or accidents while sorting, and periodic tests to verify aerosol containment inside the flow cytometer's waste disposal system. Sorting of HIV-infected specimens has been used by several CFAR investigators, and the efficiency with which the Core can offer the technique is a valuable assets of the UCLA CFAR. Center investigators also have ready access to sophisticated as well as straight-forward analytic flow cytometric techniques. Among the sophisticated techniques available that have been used by CFAR investigators are four-color immunofluorescence analysis, Ca++ flux measurements and assessments of apoptosis. Advice on experimental design, assistance with obtaining specialized reagents, and consultation on data interpretation are provided by the technical supervisor of the laboratory. The supervisor, who has ten years of flow cytometry experience, also assists investigators with development of new flow cytometric techniques or modification of existing techniques to meet their research needs. Computer equipment available in the CFAR Flow Core allows users access to the list-mode data from their experiments to perform extended evaluation of experimental results and data archiving. Network connections allow transfer of data to the user's computer environment if desired. The CFAR Core gives priority in assignment of time to projects that foster transnational research and those that involves basic and clinical research collaborations.